• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.214-219
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• 1991

To study the effect of solvents and counterions in Z-DNA crystal of d(5BrC-G-5BrC-G-5BrC-G), we performed the local energy analysis and then molecular dynamics simulations. Since counterions raise serious caging problems in crystal simulations, it is very important to search for the possible positions before simulations. For this purpose, the local energy analysis was done for the whole crystal volume. It is shown from our simulation that counterions along with water molecules play a bridging role to bind adjacent oligomers so as to form the crystal. In this crystal, each water molecule bound to Gua-N2H, either directly or indirectly, hydrates the adjacent anionic phosphate oxygen, and thus assists Gua to be in a syn position. From the simulation, the average root-mean-square deviation of allthe DNA heavy atom coordinates from the X-ray data is $0.99{\AA}$ . The bases are less deviated from the X-ray positions than the phosphates. The temperature factors from the simulation are consistent with those from the X-ray refinement, showing that the phosphates are more mobile than the bases.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.7-12
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• 1995

The purpose of this study was the development of promoter for the lacZ' gene. Two heterologous promoter I and II of lacZ' gene were isolated from chromosomal DNA Bam HI fragment of yeast. The size of the promoter I was estimated to be 2.5 kb and ${\beta}-galactosidase$ activity was 124.6 U/mg protein, and the size of the promoter II was 4.0 kb and its ${\beta}-galactosidase$ activity was 168.8 U/mg protein, respectively. The stability of the recombinant YEp plasmid in the transformant was from 52.7 to 67.4% at minimal medium. YIp plasmid was constructed from YEp plasmid, and expressed both in E. coli and yeast. The promoter I aid II iso-lated from yeast chromosomal DNA can be used for promoter of plasmid YEp and YIp.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.77-81
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• 2006

Degenerate primers corresponding to the sequences of the N-terminal regions of Mn-peroxidase isozymes were used to isolate the genomic fragments encoding the isozymes of Mn-peroxidase, CVMP1, CVMP2, CVMP3 and CVMP5 from the white-rot fungus Trametes versicolor KN9522. Three isozymes except one gave the expected PCR products (cmp1, cmp2 and cmp5) of about 900 base pairs, respectively. DNA sequence data obtained from each PCR products were used to analyze the BLAST program search on the National Center for Biotechnology Information. cmp1, cmp2 and cmp5 were similar to MPG-I (GenBank accession number Z30668) and PGV-II (GenBank accession number, Z54279) gene T. versicolor PRL572. PCR products of cmp1 and cmp2 showed 77%, 95% base sequence similarities to MPG-I gene and cmp5 showed about 88% similarity to PGV-II gene from T. versicolor PRL572. From this experiment, we could isolate genomic DNA fragments with degenerate primers designed from the N-terminal amino acid sequences of Mn-peroxidase isozyme family.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.155-161
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• 2000

Unfortunately, there is no technique which is stable and repetitive to produce transgenic chicken, although various ways of gene transfer including PGC-and embryonic cell-mediated gene transfer, DNA microinjection, virus inoculation and sperm cells have been employed. The aims of this study were 세 develop and establish such a stable, repetitive and efficient way of gene transfer giving a faithful gene expression during development after the reconstruction of embryo in an UV-irradiated egg. A dual reporter plasmid (pJJ9), a fusion gene containing lacZ and GFP driven by a CMV promoter was used to exploit either merits of both reporting markers. lacZ with strong signal or GFP with vital marking. Electroporated embryonic blastodermal cells (EBCs) in the presence of the pJJ9 DNA faithfully showed 377 bp PCR product and lacZ or GFP expressions in the identical cells in vitro of in vivo. Furthermore, analyses of expression pattern of the foreign DNA demonstrated that microinjected EBCs cells into the UV-irradiated recipient egg should participate in normal developmental process, for example, proliferation and differentiation into various tissues. Thirty percentages of the manipulated eggs showed lacZ expression in their tissues. These results together with the specific procedures used in this study should facilitate avian transgenesis.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.600-605
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• 1989

For the purpose of isolation of the Zymomonas mobilis DNA fragments showing promoter activity in Escherichia coli, a promoter screening vector, PCMT215 was constructed by transferring a promoterless chloramphenicol acetyltransferase (CAT) gene of pYEJ001 into pMT21 which contains $\beta$-lactamase gene and multiple cloning sites. A library of Z, mobilis Sau3AI DNA fragments was constructed in E. coli using the newly constructed pCMT215. Fourteen clones showing resistance to chloramphenicol ranging in concentration from 30 to 750 $\mu$g/$m\ell$ were selected. From five clones of them, the Z. mobilis DNA fragments expressing CAT gene of the recombinant plasmids were sequenced and then sites of transcriptional initiation were identified. The nucleotide sequences of the cloned DNA shared AT rich regions, poly A's or T's stretches and palindromic regions. The positions of transcriptional initiation for CAT gene occurred at more than one site spaced over by 4 to 190 base pairs on the cloned fragments in E. coli.

• Proceedings of the Korean Society of Toxicology Conference
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• 2000.11a
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• pp.45-67
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• 2000

2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is a mutagenic and carcinogenic heterocyclic amino found in cooked meat. The in vivo mutagenicity and hepatocarcinogenicity of MeIQx were examined in mice harboring the lacZ mutation reporter gene ($Muta^{TM}$ Mice) and bitransgenic mice over-expressing the c-myc oncogene. C57B1/$\lambda$lacZ and bitransgenic c-myc (albumin promoter)/$\lambda$lacZ mice were bred and weaned onto an AIN-76 based diet containing $0.06\%$ (w/w) MeIQx or onto control diet. After 30 weeks on diet, only male bitransgenic mice on MeIQx developed hepatocellular carcinoma ($100\%$ incidence) indicating that there was synergism between c-myc over-expression and MeIQx. By 40 weeks, hepatic tumor incidence was $100\%$ ($17\%$) and $44\%$ ($0\%$) in male c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice given MeIQx (or control) diet, respectively, indicating that either MeIQx or c-myc over-expression alone eventually induced hepatic tumors. At either time point, mutant frequency in the lacZ gene was at least 40-fold higher in MeIQx-treated mice than in control mice of either strain. These findings suggest that MeIQx-induced hepatocarcinogenesis is associated with MeIQx-induced mutations. Elevated mutant frequency in MeIQx-treated mice also occurred concomitant with the formation of MeIQx-guanine adducts as detected by the $^{32}P$-postlabeling assay. Irrespective of strain or diet, sequence analysis of the lacZ mutants from male mouse liver showed that the principal sequence alteration was a single guanine-base substitution. Adenine mutations, however, were detected only in animals on control diet. MeIQx-fed mice harboring the c-myc oncogene showed a l.4-2.6-fold higher mutant frequency in the lacZ gene than mice not carrying the transgene. Although there was a trend toward higher adduct levels in c-myc mice, MeIQx-DNA adduct levels were not significantly different between c-myc/$\lambda$lacZ and C57B1/$\lambda$lacZ mice after 30 weeks on diet. Thus, it appeared that factors in addition to MeIQx-DNA adduct levels, such as the enhance rate of proliferation associated with c-myc over-expression, may have accounted for a higher mutant frequency in c-myc mice. In the control diet groups, the lacZ mutant frequency was significantly higher in c-myc/$\lambda$lacZ mice than in 057B1/$\lambda$1acZ mice. The findings are consistent with the notion that c-myc over-expression is associated with an increase in mutagenesis. The mechanism for the synergistic effects of c-myc over-expression on MeIQx hepatocarcinogenicity appears to involve an enhancement of MeIQx-induced mutations.

• BMB Reports
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• v.30 no.3
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• pp.188-193
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• 1997

Membrane lipid peroxidation processes yield products that may react with DNA to cause mutations. Lipid hydroperoxides from linoleic acid in the presence of transition metal ions caused strand breaks in plasmid DNA. DNA damage induced by reactive aldehydes known to be produced by decomposition of lipid hydroperoxides, such as 4-hydroxynonenal or rnalondialdehyde, was repaired by endonucleases and exonuclease III which resulted in the increase of single strand breaks in DNA. Lipid hydroperoxides as well as malondialdehyde and 4-hydroxynonenal also caused mutations in the pUC18 lacZ' gene when measured as a loss of ${\alpha}-cornplementation$. In conclusion. the lipid peroxidation could be an important intermediary event in DNA damage and mutation by oxidative stress.

• Interdisciplinary Bio Central
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• v.1 no.1
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• pp.4.1-4.7
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• 2009

Introduction: Histone modifications and DNA methylation are the major factors in epigenetic gene regulation. Especially, revealing how histone modifications are related to DNA methylation is one of the challenging problems in this field. In this paper, we address this issue and propose several plausible mechanisms for precise controlling of DNA methylation status at CpG islands. Materials and Methods: To establish the regulatory relationships, we used 38 histone modification types including H2A.Z and CTCF, and DNA methylation status at CpG islands across chromosome 6, 20, and 22 of human CD4+ T cell. We utilized Bayesian network to construct regulatory network. Results and Discussion: We found several meaningful relationships supported by previous studies. In addition, our results show that histone modifications can be clustered into several groups with different regulatory properties. Based on those findings we predicted the status of methylation level at CpG islands with high accuracy, and suggested core-regulatory network to control DNA methylation status.

• Asian Journal of Turfgrass Science
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• v.10 no.4
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• pp.275-283
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• 1996

An investigation was performed to reveal the relation between the storage and decomposition of the titter DNA of a Zoysia japonica grassland on Mt. Kwanak. The loss constant k of litters was 0.167. The times required for the decomposition of half, 95% and 99% of accumulated DNA on the grassland floor were 3.8, 16.6 and 27.6, respectively. The amount of DNA which is turned to living organism in the ecosystem is higher than that of crude protein. In the case of crude protein, the decay constant k was 0.181. The times needed for the decomposition of half, 95% and 99% of accumulated crude protein on the Z. japonica grassland floor were 3.8, 16.6 and 27.6 years, respectively. Key words: Zoysia japonica, Mt. Kwanak, Litter DNA, Crude protein, Decomposition, Accumulation.

• Natural Product Sciences
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• v.10 no.6
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• pp.272-276
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• 2004

During the course of our screening for bioactive metabolites from marine sponges, EZZ, the inseparable 1:1 mixture of (8E,13Z,20Z)-strobilinin and (7E,13Z,20Z)-felixinin has been found to deliver significant cytotoxicity against some cancer cell lines. In this study, the antioxidant activity of EZZ was first time evaluated by a series of antioxidant assays. It was found that EZZ was weak in scavenging the stable free radical 1,1-diphenyl-2-picrylhyrazyl (DPPH), but it was comparable to ascorbic acid in scavenging ABTS and superoxide radicals. In addition, EZZ could protect DNA from hydroxyl radical-induced strand cleavage. The findings of the present study suggest that EZZ possess certain antioxidant activity, which might help to prevent occurrence of cancer by alleviating the oxidative stress in cells.